Page 189 - Maths Class 06

Symmetry

Introduction

Often in our everyday life, we see many figures which are balanced in nature. These
types of figures which have evenly balanced proportions, are called symmetrical
figures.

Look at figure given alongside. It is a fish called Tinny.
If we draw a line vertically in middle of its body, we will see that the two sides on Fig. 13.1
either side of the line are symmetrical in nature. It has fins, scales, tail which are divided in exactly half by
the dotted line. Thus the body parts of it are balanced on either side of the line. This property of balancing
is known as symmetry, and the dotted line on which it
balance, is known as line of symmetry.

Around us, we see many figures of such kind, which
have a kind of symmetry in them. Some figures which
are symmetrical are given in Fig. 13.2. In each figure,
(i) (ii) (iiii) (iv) (v)
the dotted line is the line of symmetry.
Fig. 13.2
Classroom Activities

Making Symmetrical Figures From Ink
As a classroom activity we can make unique symmetrical figures from
ink. For this do the following:
Take a piece of a paper. Draw a dotted line in middle of it. By dropping
ink on it, make a figure on one side of the line. Now fold it along the
line. Press the paper, gently in the beginning and later on with firm
hands. Now unfold the paper. What will you find? A figure symmetrical
Fig. 13.3
to earlier figure. Note that both the figures are mirror image of each
other. The line we have drawn is the mirror line.

Making a Figure by Cutting the Paper
For this activity, take a piece of paper and fold it as shown
in the Fig. 13.4. On the folding line of the paper, draw half
shape of a figure and cut it with scissors.
Now unfold the paper, you will have a full figure with two
mirror parts. Also both the parts are symmetrical to each
other.
Fig. 13.4

189 Mathematics-6